I would think that hosting your sites from your home would be a step down from renting a dedicated server. What you should be thinking about is colocating a server. Colocation can sometimes be more expensive, but can work out really great if you go with the right company.
Some things to consider are how long-term your plans are, if you need a lot of additional speed, if you need a more fail safe server, if you're willing to deal with the usually small inconvenience of managing the hardware aspects, etc.
Long-term, I think colo is generally a better idea than renting dedicated servers but there are benefits to staying with dedicated servers, though.